1. Field of the Invention
The present invention relates to a high-frequency module that transmits and receives multiple communication signals with a common antenna.
2. Description of the Related Art
Various high-frequency modules that each transmit and receive multiple communication signals using different frequency bands with a common antenna are known. Such high-frequency modules include, for example, high-frequency modules described in Japanese Unexamined Patent Application Publication No. 2003-152588 and Japanese Unexamined Patent Application Publication No. 2006-333127.
The high-frequency modules described in Japanese Unexamined Patent Application Publication No. 2003-152588 and Japanese Unexamined Patent Application Publication No. 2006-333127 each include a switch integrated circuit (IC) and multiple demultiplexers. A high-frequency module described in Japanese Unexamined Patent Application Publication No. 2007-97117 includes a surface acoustic wave duplexer (hereinafter referred to as a SAW duplexer).
Many such high-frequency modules are reduced in size in order to, for example, be used for mobile communication terminals. A high-frequency module has been proposed in which internal electrode patterns of a multilayer body are combined with mounting circuit elements (for example, SAW duplexers) mounted on the multilayer body.
However, the spacing between the mounting circuit elements mounted on a front surface of the multilayer body is decreased as the high-frequency module is increasingly reduced in size. In particular, when the mounting circuit elements are demultiplexers, such as duplexers, the decrease in the spacing between the demultiplexers causes interference between the demultiplexers to be likely to occur. As a result, a problem is caused in which the isolation between the communication signals is likely to be reduced.